Western campaigns by Union forces earlier in 1862 had reaped much progress. The Tennessee and Cumberland Rivers had been opened to the U.S. Navy after successes at the battles of Fort Henry and Fort Donelson. The railroad hub at Corinth had been evacuated by the Confederates, causing most of West Tennessee to fall into Union control. New Orleans, the Confederacy's largest city at that time, had been captured by Admiral David Farragut. The city of Vicksburg, Mississippi, was now an important strategic aim for the Union commanders, as the western Confederates were "narrowed down all to the single line of [rail]road running east from Vicksburg."[1] Consequentially, protecting the Confederate stronghold on the Mississippi River became a top priority for the Confederacy. Confederate General Braxton Bragg decided to avert Union attention away from Vicksburg and from Chattanooga, Tennessee, which was being threatened by a large Union force under Don Carlos Buell, by invading the border state of Kentucky.

Kirby Smith pleaded with Bragg to follow up on his success: "For God's sake, General, let us fight Buell here." Bragg replied, "I will do it, sir," but then displaying what one observer called "a perplexity and vacillation which had now become simply appalling to Smith, to Hardee, and to Polk,"[2] he ordered his army to retreat through the Cumberland Gap to Knoxville. Bragg referred to his retreat as a withdrawal, the successful culmination of a giant raid. He had multiple reasons for withdrawing. Disheartening news had arrived from North Mississippi that Earl Van Dorn and Sterling Price had failed at Corinth, just as Robert E. Lee had failed in his Maryland Campaign. He saw that his army had not much to gain from a further, isolated victory, whereas a defeat might cost not only the bountiful food and supplies yet collected, but also his army. He wrote to his wife, "With the whole southwest thus in the enemy's possession, my crime would have been unpardonable had I kept my noble little army to be ice-bound in the northern clime, without tents or shoes, and obliged to forage daily for bread, etc."[3]

Aftermath

The invasion of Kentucky was a strategic failure, although it had forced the Union forces out of Northern Alabama and most of Middle Tennessee; it would take the Union forces a year to regain the lost ground. Bragg was criticized by some newspapers and two of his own generals, Polk and William J. Hardee, but there was plenty of blame to spread among the Confederate high command for the failure of the invasion of Kentucky. The armies of Bragg and Kirby Smith suffered from a lack of unified command. Bragg can be faulted for moving his army away from Munfordville, out of Buell's path, a prime location for a battle to Confederate advantage. Polk can also be blamed for not following Bragg's instructions on the day before and of the battle. Davis kept Bragg in command of the Army of Tennessee. Lincoln removed Buell from command of the Army of the Ohio for being too cautious in pursuit of Bragg, replacing him with Major General William Rosecrans.